How to choose an E+H ultrasonic level meter

Choosing the right Endress+Hauser (E+H) ultrasonic level measurement instrument requires a comprehensive assessment of various factors to ensure reliable and accurate operation in your specific application. Here are the main selection considerations and steps:

1.   Understand Medium Characteristics:

•   Medium Type: Is it a liquid (water, wastewater, acids, alkalis, etc.), slurry, sludge, or bulk solid (granules, powders, lumps)? Ultrasonic technology relies on sound wave propagation, and its effectiveness can be significantly impacted by the medium. For example, loose powders or environments with significant foam, heavy vapor, or dust can severely attenuate the ultrasonic signal.
•   Density, Viscosity: While ultrasound is primarily affected by the speed of sound in the gas phase above the medium, the density and viscosity of the medium can influence its surface conditions, which in turn affects measurement.
•   Corrosiveness/Abrasiveness: If the medium is corrosive or abrasive, you need to select sensor probe materials (e.g., PVDF, PTFE) that offer good resistance to these conditions.

2.   Determine Process Conditions:

•   Temperature: The speed of sound in air is affected by temperature. High-quality ultrasonic level meters typically have built-in temperature compensation. However, you must ensure the instrument's operating temperature range covers your process temperature.
•   Pressure: Ultrasonic measurement is non-contact, so it is not sensitive to internal vessel pressure. However, in open vessels, atmospheric pressure changes might slightly affect accuracy (usually negligible).
•   Vacuum/High Pressure: Ultrasonic sensors are generally not suitable for measurements inside vessels under vacuum or high pressure (radar or guided wave radar should be considered in such cases).
•   Vapor, Foam, Dust: These are major challenges for ultrasonic measurement. They can absorb or scatter the ultrasonic signal, leading to unstable or failed measurements. In such conditions, radar level meters should be prioritized.
•   Agitators, Obstructions: Are there agitators, coils, support beams, or other obstructions inside the vessel? These can interfere with the propagation path of the ultrasonic signal. You'll need to choose an appropriate mounting location or an instrument with signal blanking functions.

3.   Define Measurement Requirements:

•   Measuring Range (Span): What are the maximum and minimum liquid or bulk solid levels you need to measure? E+H ultrasonic level meters have different range capabilities (e.g., Prosonic FMU90 can reach up to 45 meters). Selecting the appropriate range ensures accuracy and avoids unnecessary costs.
•   Measurement Accuracy: What level of measurement accuracy is required? Ultrasonic level meters can typically provide millimeter-level accuracy, but it might decrease in extreme conditions.
•   Blind Zone and Safe Distance: Ultrasonic sensors require a certain amount of time to transmit and receive signals, creating a "blind zone" near the sensor where effective measurement is not possible. The lowest liquid level must be above this blind zone during installation.

4.   Consider Installation and Environmental Conditions:

•   Mounting Position: Is there enough space at the top of the vessel to mount the sensor? Can the sensor be mounted perpendicular to the medium's surface?
•   Vessel Shape: The shape of the vessel (e.g., cylindrical, spherical, horizontal tank, conical bottom tank) can affect signal reflection and linearization. E+H instruments usually support linearization for various tank shapes.
•   Hazardous Area Requirements: If the instrument is to be installed in a hazardous area, you must select a model that complies with the relevant explosion protection certifications (e.g., ATEX, IECEx).
•   Ingress Protection (IP Rating): Does the instrument need protection against dust and water? Typically, IP65, IP66, or higher ratings are chosen.
•   Power Supply and Output Signal: What type of power supply does the instrument require (e.g., 24V DC, 220V AC)? What kind of output signal is needed (e.g., 4-20mA, HART, Profibus DP, Modbus)?
•   Display and Operation: Is a local display and push-button operation required? Does it support remote configuration and diagnostics (e.g., via FieldCare software)?

5.   E+H Product Series Selection (Prosonic Example):

E+H's ultrasonic level meters primarily fall under the Prosonic series, such as:

•   Prosonic FMU90: A powerful and flexible separate-type level meter that can be used with different probes (e.g., FDU9x series). It's suitable for level measurement of liquids, slurries, sludge, and bulk solids, and can also be used for open channel flow measurement and pump control. It features various communication interfaces and diagnostic functions, making it suitable for complex applications.
•   Prosonic FMU30 (Compact): A more compact, all-in-one design where the sensor and transmitter are integrated. It's simpler to install and more cost-effective, suitable for general water treatment and utility level measurements.

Recommended Selection Process:

1.   Preliminary Screening: Based on the medium type, measuring range, process temperature, and pressure, determine if ultrasonic technology is suitable. If the medium surface has significant foam, dust, heavy vapor, or if there's a vacuum/high pressure, it's often better to prioritize radar level meters.
2.   Define Core Needs: Clearly outline your specific requirements for accuracy, functions (like pump control, flow calculation), communication methods, and hazardous area classifications.
3.   Select Instrument Series: Choose between a compact (e.g., FMU30) or separate (e.g., FMU90 + FDU probe) series based on application complexity and budget. Separate-type instruments offer more flexibility for challenging conditions.
4.   Configure Detailed Parameters: Refer to the selection manual to configure parameters such as probe type, measuring range, process connection, housing material, hazardous area rating, electrical connection, and output signal, according to your specific tank dimensions, mounting location, and medium characteristics.
5.   Consult E+H or Authorized Distributors: Endress+Hauser provides professional pre-sales technical support. Before making a final selection, it is highly recommended to contact their sales engineers or authorized distributors. Provide them with detailed information about your operating conditions, and they can offer the most suitable recommendations and specific model configurations based on their expertise.

By following these steps, you can systematically evaluate your needs and choose the most appropriate E+H ultrasonic level measurement instrument for your application. Choosing the right Endress+Hauser (E+H) ultrasonic level measurement instrument requires a systematic approach, considering various factors to ensure optimal performance in your specific application. Here's a guide to help you make an informed decision:

1.   Understand the Medium Characteristics:

•   Medium Type: Is it a liquid (e.g., water, wastewater, acids, alkalis), a slurry, sludge, or bulk solid (e.g., granules, powders, coarse materials)? Ultrasonic technology relies on sound wave propagation; loose powders, heavy foam, strong vapors, or dust can severely attenuate the ultrasonic signal.
•   Density & Viscosity: While ultrasonic measurement is primarily affected by the speed of sound, the density and viscosity of the medium can influence its surface conditions, thereby impacting the measurement.
•   Corrosiveness/Abrasiveness: If the medium is corrosive or abrasive, select a sensor with probe materials (e.g., PVDF, PTFE) that offer good resistance.

2.   Determine Process Conditions:

•   Temperature: The speed of sound in air is affected by temperature. High-quality ultrasonic level meters from E+H typically have integrated temperature compensation. Ensure the instrument's operating temperature range covers your process temperatures.
•   Pressure: Ultrasonic measurement is non-contact and generally unaffected by pressure inside the vessel. However, for applications involving vacuum or high pressure inside closed vessels, ultrasonic is not suitable; radar or guided wave radar would be better choices.
•   Steam, Foam, Dust: These are significant challenges for ultrasonic measurement. They can absorb or scatter the ultrasonic signal, leading to unstable or failed readings. In such conditions, radar level meters should be prioritized.
•   Agitators, Obstructions: Are there agitators, coils, support beams, or other internal obstructions in the tank? These can interfere with the ultrasonic signal path. You might need to select an appropriate mounting position or a device with echo mapping/suppression capabilities.

3.   Define Measurement Requirements:

•   Measurement Range (Span): What are the maximum and minimum levels you need to measure? E+H ultrasonic level meters (e.g., Prosonic FMU90) offer various ranges (up to 45 meters). Selecting the correct range ensures accuracy and avoids unnecessary costs.
•   Accuracy: What level of measurement accuracy is required? Ultrasonic level meters typically provide millimeter-level accuracy, but this can degrade under extreme conditions.
•   Blind Zone (Blocking Distance): Ultrasonic sensors have a "blind zone" close to the sensor where effective measurement cannot occur. Ensure that your lowest process level is outside this blind zone.

4.   Consider Installation & Environmental Conditions:

•   Mounting Location: Is there enough space on top of the vessel for sensor installation? Can the sensor be mounted vertically to the media surface?
•   Vessel Shape: The shape of the vessel (e.g., cylindrical, spherical, horizontal tank, conical bottom) can affect signal reflection and linearization. E+H instruments often support linearization curves for various tank shapes.
•   Hazardous Area Requirements: If the installation is in a hazardous area, select an instrument model that complies with relevant explosion protection certifications (e.g., ATEX, IECEx).
•   Ingress Protection (IP Rating): Does the instrument need protection against dust and water? Generally, IP65, IP66, or higher ratings are preferred for outdoor or wash-down environments.
•   Power Supply and Output Signal: What type of power supply does the instrument require (e.g., DC 24V, AC 220V)? What output signal is needed (e.g., 4-20mA, HART, Profibus DP, Modbus)?
•   Display and Operation: Is a local display and push-button operation required? Does it need to support remote configuration and diagnostics (e.g., via FieldCare software)?

5.   E+H Product Series Selection (Prosonic Example):

E+H offers the Prosonic series for ultrasonic level measurement, with popular models including:

•   Prosonic FMU90: This is a powerful and flexible separate version (transmitter and sensor are separate units). It can be combined with different sensors (e.g., FDU9x series) and is suitable for level measurement of liquids, slurries, sludges, and bulk solids. It also supports open channel flow measurement and pump control. It features various communication interfaces and diagnostic functions for complex applications.
•   Prosonic FMU30: This is a more compact compact version (sensor and transmitter integrated). It's easier to install and more cost-effective, often used for general water treatment and utility applications.

Recommended Selection Process:

1.   Initial Screening: Based on media type, measurement range, and process temperature/pressure, determine if ultrasonic technology is suitable. If significant foam, dust, heavy steam, vacuum, or high pressure are present, prioritize radar level meters.
2.   Define Core Needs: Specify your exact requirements for accuracy, additional functions (like pump control, flow calculation), communication options, and hazardous area certifications.
3.   Choose Instrument Series: Based on application complexity and budget, select between an integrated unit (e.g., FMU30) or a separate unit (e.g., FMU90 + FDU sensor). The separate version offers more flexibility for challenging conditions.
4.   Configure Detailed Parameters: Using the E+H selection guide or product configurator, specify sensor type, measuring range, process connection, housing material, explosion protection, electrical connection, and output signals based on your tank dimensions, mounting position, and media properties.
5.   Consult E+H or an Authorized Distributor: Endress+Hauser provides professional pre-sales technical support. Before making a final decision, it is highly recommended to contact their sales engineers or authorized distributors. Provide them with your detailed process conditions and requirements, and they can offer expert recommendations and assist with specific model configurations.